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Discussion Starter #1
I am installing Koni rear shocks with OE springs....

Which 'ring' on the shock assembly should be used for the lower mounting point for the spring? (See attached image) The shocks were delivered with the O-ring in the middle position.

Also I welcome any and all corrections on the terminology I've used. I prefer to use proper nomenclature, but in this case I'm not sure what terms are accurate. :M5thumbs:

Thanks!
 

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once you pull out the oem shocks it will be very obvious. Just lay the OEM shock and Koni side by side and you will see. BTW its a lower spring perch :byee55amg
 

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Discussion Starter #3
Just in case it's not so obvious to me...ouich Which of the grooves did you place the o-ring in.

Also, can you help me understand what the implications of a lower spring perch are?

If I follow, you mean that the lower (bottom) spring perch is somewhat lower that the OE position. If that conclusion is correct, then what does that imply, if anything?

Thanks!
 

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I think he just meant that what you called the "lower mounting point for the spring" is called the lower spring perch. Further, I CarbonBeast also meant that when you take the OEM shock off the car, you can line it up with the Koni to see which ring channel is the same distance from the lower bolt hole. If not, you can measure the OEM distance and then place the ring in the equivalent location.

Chuck
 

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Discussion Starter #5 (Edited)
Now I got it! :thumbsup: (I interpreted his reply incorrectly on the first go-round.)

So the proper terminology for this component is: 'lower spring perch', and on the Koni, there are three different positions to choose from, one of which will be closest to the OE dimensions of the lower bolt hole to lower spring perch. (Sounds easy enough :D )

Assuming it is the middle position, does anyone know what the effects are if I choose the lower one? The higher one?
 

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I think you should take it all to a pro I can see this going south real quick.

you need a spring compressor to remove the spring from the factory shock so you don't bust up everything too.
 

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Spring compressor is not needed in the rear. There is no significant spring preload when the shock is fully extended. This is why higher rate linear springs are not sold for the stock perches.
 

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I thought I was getting Altzheimers, but no....not yet.

It seems Koni just made another revision to their E39 rear shocks. Notice oldranger's shocks have three grooves for perch adjustment. Last year's Koni's had only 2 grooves. What is the part# of these shocks? Perhaps Koni released a V8-onlt rear shock? I wouldn't think so with so many grooves for universal fit. Earlier E39 Koni V8 rear shocks are shared with 6 cyl E39 cars.
 

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Discussion Starter #9 (Edited)
Lscman: the part number is 8240-1156SPORT. The space between the rings is 1/2 inch, the ring is 1/16 inch thick.

Jayson: Thanks for your concern. Although I happen to be unfamiliar with this Koni design, I'm familiar with the risks of working with springs. When I changed my front struts a couple weeks back, I elected to take the strut assemblies to a "pro" to have the dampers swapped. Modern shops have much better tooling (wall mounted spring compressors) that have all the safety features and accomodate a deliberate disassembly/reassembly. I did the installation myself. :thumbsup:

I agree with CarbonBeast that it will be self-evident when I remove the OE shock/spring what the closest match is for the lower perch. In the event that it is not an exact match - I wanted to hear others opinions on what they anticipate the effects of choosing the lower vs. the higher perch would be. I'd rather go through this analysis prior to starting the job, and if it turns out there is an exact match from lower bolt hole to lower spring perch - all the better.:M5thumbs:

In my experience working with them, many mechanics/techs would do the visual match, and walk right through this step without much consideration. (I mean no offense by this, I have a tremendous respect for mechanics who are highly competent)

Thanks guys!
 

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Discussion Starter #10
Installation is complete

Konis are in! :D

The lowest of the three perch settings is equivalent to the OE shock with respect to distance from lower bolt hole to the perch.

Install was pretty straight-forward, and although I agree with Lscman that a spring compressor is not required, it did make reassembly a little easier :M5thumbs:

OBTW - the yellow paint finish is brittle and has very little adhesion to the metal of the damper. So if you are going to be peculiar about how the finish looks after install - you will have to be very deliberate during install. (plan extra time and bring a lot of patience)
 

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I've heard the rears are a ***** to install -- congrats!
 

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Discussion Starter #12
CSBM5 said:
I've heard the rears are a ***** to install -- congrats!
Thanks. :cheers: I'll have to say that the work to remove the interior components to gain access to the shocks was much easier than I anticipated.

The only part I really struggled with was re-assembly of the lower bolt on the shock. The suspension at full droop twists in a way that makes it difficult to orient the lower bolt hole of the shock to the wheel hub carrier. I found that the rear link must remain disconnected in order for you to twist and orient the wheel hub carrier to accept the lower shock bolt. This step is tough without a helper; definetly an ibuprofen exercise. I better go take some before I hit the rack.
 

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Discussion Starter #13 (Edited)
Lscman, you've been very helpful already - but I'm coming back for more help if you can spare the time. :typing: After the Konis went in the rear, the ride height in the rear increased slightly. This is not preferable, especially with the lowering on the front from the H&R 29441s. Here's current state:

RF = 13 3/8 in. (H&R 29441, Koni)
LF = 13 1/2 in. (H&R 29441, Koni)

RR = 14 3/8 in. (OE spring, Koni on lowest perch)
LR = 14 3/8 in. (OE spring, Koni on lowest perch)
Dinan Rear Sway in middle setting

I reviewed one of your posts from last year that you experienced a similar 'elevation' in ride height after Konis were installed with fresh spring cushions. Was it temporary (unlikely), or do you still have ride heights of over 14" in the rear?

Note: the car handles quite well - very neutral, but I can't get over the aesthetics (too low in front/too high in rear). There's also the likelihood that the balance is off. I'm contemplating what I will do to fix the situation, and there are a few courses of action I've considered, what do you think?

1. Add KMACs to the front to even the ride height out as well as allow camber adjustments, and deal with the sub-par manufacturing (some endorse this product).
2. Check if GC's camber plates would raise ride height and install those if 'yes' to even the ride height as well as allow camber adjustments.
3. Put the OE front springs back in to even up ride height and install GC camber plates in the process for the intended affect of camber adj.
4. Order Dinan springs (front and rear) and start all the way over.
According to other posts, these springs achieve a balanced, slightly lower ride height.

:confused:

Thanks! (OBTW - my pictures in 'View my Car' are with the Koni/H&R in the front, but before I replaced the OE shocks with Konis in the rear)
 

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I need some questions answered before making suggestions:

I am not clear exactly what you did in the rear.

1) Did you retain OEM upper strut mounts or did you install the GC mounts?
2) Did you reuse your old rear springs or buy new OEM?
3) Did you reuse your old spring perch cushions or buy new from BMW?
4) Is the final clip position in the bottom slot? I noticed the middle slot in the pics. I am unclear why you used a spring compressor to install. This makes me very suspicious.

One observation:

With respect to the front, it sounds like H&R springs vary in loaded height. If you search archives for Elevens 29441 spring fitment, you'll see he got something like 14" in front.
 

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Discussion Starter #15
Lscman,

1) I retained the OEM upper strut mounts.
2) I reused the rear springs.
3) I reused the spring perch cushions.
4) I moved the clip on the Koni to the slot closest to the lower bolt hole before I assembled the spring/shock (I used the lowest spring perch). It was essentially and exact match to the OE dimension.

I used a spring compressor to reassemble the springs because I found that I was unable to compress the springs with my body weight on top of the upper mount enough to get the nut threaded on the top of the Koni shock 'rod'. It was close, but I preferred to slightly compress the spring with tools. If I had three hands this might not have been required. ;-)

With respect to the front, the low ride height of the H&R 29441 springs is kind of a surpise to me (especially LF). When the front strut assemblies were returned to me by the shop that assembled them - the H&R spring had literally no preload. Although minimally, I could wiggle the spring around in the cushions. That said, they are clearly labeled 29441.
 

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I'll have to look at my paperwork, but I thought Koni set the clip in the middle as thats for the stock spring/stock ride height.
Don't the front H&R lower 1.25/1.5" when installed?
Then setting the rear to the lowest is a .5" drop.
That would be about 1" higher in the rear then.

Now the question I thought of when I first read this.

What did you set the rear strut valving to? Factory?
cherrsagai
 

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Discussion Starter #17
6spd,

6spd said:
I'll have to look at my paperwork, but I thought Koni set the clip in the middle as thats for the stock spring/stock ride height.
Don't the front H&R lower 1.25/1.5" when installed?
Then setting the rear to the lowest is a .5" drop.
That would be about 1" higher in the rear then.
If I interpret your post correctly, do you mean to say that the ride heights I have should be expected? I agree on the front...but I did not expect to see the rear ride height increase when I put the Konis in. I don't have the exact original rear ride heights recorded, but I recall them to be very close to 14 in.

6spd said:
What did you set the rear strut valving to? Factory?
I set the Koni valving to 3/4 turn from full soft.
 

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OldRanger,

How much different was the spring compression in the unloaded state between the OEM and what you had to do with the Koni? I'm just wondering if the overall length of the Koni was a bit shorter than the OEM; hence, you needed to use the spring compressor a tad and now with the spring in pre-load in the unloaded state, it then results in a higher static ride height in the loaded state....just thinking out loud here.

Chuck
 

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Discussion Starter #19
CSBM5 said:
How much different was the spring compression in the unloaded state between the OEM and what you had to do with the Koni?
Chuck, thanks for helping with the problem solving!

Good question, but I'm not sure what the difference was. The technique/tools I used to dissamble the OE shock/spring prevented me from really assessing it, but I would have to assume it was nearly equivalent. Like I mentioned in an earlier post - I only used the spring compressor for reassembly with the Konis because I didn't have a helper. Otherwise, my body weight (with both hands on the upper mount) was enough to compress the spring sufficiently to get the nut threaded. I just didn't have a 'third hand' around. :typing:
 

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OldRanger said:
Lscman,

1) I retained the OEM upper strut mounts.
2) I reused the rear springs.
3) I reused the spring perch cushions.
4) I moved the clip on the Koni to the slot closest to the lower bolt hole before I assembled the spring/shock (I used the lowest spring perch). It was essentially and exact match to the OE dimension.

I used a spring compressor to reassemble the springs because I found that I was unable to compress the springs with my body weight on top of the upper mount enough to get the nut threaded on the top of the Koni shock 'rod'. It was close, but I preferred to slightly compress the spring with tools. If I had three hands this might not have been required. ;-)

With respect to the front, the low ride height of the H&R 29441 springs is kind of a surpise to me (especially LF). When the front strut assemblies were returned to me by the shop that assembled them - the H&R spring had literally no preload. Although minimally, I could wiggle the spring around in the cushions. That said, they are clearly labeled 29441.
1) The rear ride height increased slightly because the Koni's have plenty of gas pressure and the factory Boge's were blown out. The measurements you provide are what I'd expect with stock springs and Koni's. The nature of the M5 rear spring design allows you to cut one end off with a hacksaw to lower the car. One end has tighter-wound coils and this is the end that gets cut. The finished spring uncompressed length can not be cut much under 13" or preload will be lost & the spring will need to be scrapped. Removing 1/2 coil will drop the car at least 1/2". This is an unexact science, unless you are able to closely measure the coil stack configuration with the car at rest under load. In that case, careful measurements can tell you how much to cut. This is not the solution, since your 29441 is too short.

2) The front 29441 H&R spring set you got is flawed. Compare your ride heights to Elevens old post with pics. The uncompressed length is simply too short by about 3/4" to 1"...H&R messed up during fabrication & they need returned for credit. The only alternative is to carefully fabricate a 3/4" spacer made of heavy rubber product to fit under the lower spring cushion. Certain industrial gasket products would suffice. This effort would be quite time-consuming, although the result would be fine. There is nothing wrong with using a spring spacer of good design & fitment.

What you're going to discover is achieving desired ride heights with non-adjustable parts is almost impossible. I have watched folks concerned about ride heights juggle springs 3 or more times. Many folks have gotten odd ride heights with Dinan and other kits. If you review archives here, you will see M5 Dinan cars with ride heights varying wildly. Some sit a whopping 1" higher in the front. This looks sillier than your car. Dinan springs have been shipped in various lengths, as they seem to be changing suppliers every year or so to achieve low bid or something.

If you want particular ride heights, you should buy a coil-over system and be done with it. GC sells their kit less Koni's for around $1200 with adjustable upper mounts. The proper spring rates would probably be Drallen's 430 front with a rear spring around 350-375. Without adjustable coil-overs you might wind up swapping springs several times.

Another option for raising the front is different strut mounts or spacers, although, I do not like the fact that your spring is loose in the perch. It will only get looser as the spring sags another 1/4" or so in the next months from settling/break-in.

BMW also sells a "rough road spacer" for 540i and other models that would fit the M5 perfectly. It's sole function is to raise ride height. It is a sort of lame solution for raising ride height because the jounce is not as good as choosing proper length spring. The spacer is basically a puck with a clearance hole drilled in the middle that fits under the shock tower above the strut mount. It has 3 little mounting holes in it for the strut mount studs. It is basically a spacer much like the Dinan plate, except it's symettrical and does not alter camber.

The GC strut mount for stock springs may or may not raise the car. I don't know the answer.

The KMAC's will add 5/16" ride height. Problem is they are nasty, unless you can get local MIB to call somebody to hand-pick you a pair of good ones off the Australian assembly line. KMAC's QA/QC is the worst I've ever seen from any company and the sheetmetal they use for the mount is "scary" thin. It looks to be made of 18 gauge sheetmetal, befitting a 2500lb Subaru. The upper and lower half is spotwelded together in a very haphazard fashion. Can you imagine whacking a pothole with a strut mount fabricated of 18 gauge sheet? The thing may fail or bend & stress the strut tower.


**by the way, for R&R, I would suggest leaving the upper rear mounts attached. When I install rear springs or shocks on an E39, I install the lower perch and the fully compress the shock rod and restrain it with strong, stiff copper wire of about 12 gauge. This can be done by tying a knot on the threaded end and running the wire through the eyelet on the other end. At this point, the shoc is compact and easy to deal with. Once you get the shock positioned down thru the spindle assy, the spring can be set on top & the copper wire can be cut to allow the rod to pas up through the spring, upward into the mount. You will discover the lower bolt can now be installed and the rod threads will pass up through the upper mount with no compressor. Suspension links do not need removed.
 
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